torsocks on и не должен так работать. Нужно делать source для скрипта torsocks.
Из мана
on | off - This option adds or removes torsocks(8) from the LD_PRELOAD
environment variable for the current shell. If you want to use this option, you
HAVE to source torsocks from your shell.
Add the torsocks library to LD_PRELOAD
$ . torsocks on
Remove the torsocks library from LD_PRELOAD
$ . torsocks off